A 5-year-old boy riding his bike is in serious condition after he was hit by a van in the Cabana Colony neighborhood in Palm Beach Gardens, authorities said.The accident happened at about 6:30 p.m. in the 12000 block of Dinghy Road, authorities said.According to Palm Beach County Fire Rescue Capt. Don DeLucia, the child was taken by ambulance to St. Mary's Medical Center in West Palm Beach where he remains in serious condition.